1. Field of the Invention
The invention relates to an assembly of the kind comprising a flexible diaphragm, two clamping members and a band, wherein a peripheral portion of the diaphragm is clamped between respective clamping surfaces on the clamping members, peripheral portions of the clamping members are embraced by the band and the band is subjected to tension to establish and maintain pressure contact between the diaphragm and the clamping members. In an assembly of this kind, the band has a transverse cross-section which includes two limbs between which the peripheral portions of the clamping members are received. The band commonly has a transverse cross-sectional shape approximating to that of a `U` with the limbs diverging from each other. For establishing tension in the band, there is commonly provided a screw and nut which cooperate with housings provided on opposite end portions of the band. The band of an assembly of this kind is commonly referred to as a "V-band clamp".
2. Description of the Prior Art
Assemblies of the kind referred to are used in air-operated diaphragm pumps wherein a medium which is to be pumped is separated from air by the diaphragm. In known assemblies of this kind used in diaphragm pumps, mutual approach of the clamping surfaces is limited only by the diaphragm. Whilst it is possible to establish at least approximately a predetermined pressure between the diaphragm and the clamping surfaces by applying a predetermined torque to the nut of a screw and nut mechanism of the band, excessive tightening of the band is possible with known arrangements, thereby increasing the pressure beyond the optimum amount. If the peripheral portion of the diaphragm is subjected to excessive stress, it will be permanently deformed or otherwise damaged.
A further disadvantage of the known arrangements is that the radial position of one clamping member relative to the other clamping member is not accurately controlled by the band. There is freedom for some degree of misalignment and, since the peripheral portions of the clamping members are covered by the band, it is not easy to check visually that the clamping members are properly sligned with each other.